Intake-tjitloadeb



C. WAINWRIGHT.

INTAKE UNLOADER FOR COMPRESSOR SERVICE. APPLICATION FILED MAY 11. 1919.

1 324,705, Patentd Dec. 9, 1919;

Q JP J' i 0 J M J" U A x X UNITED STATES PATENT OFFICE.

cnARLEs wemwmenr, or mun, r N vsYLvANIA.

Application filed May 17, 1919.

To all whom it may concern:

Be it known that I, CHARLES WAIN- WRIGHT, a citizen of the United States, residing at Erie, in the county of Erie and State ofv Pennsylvania, have invented. new

and useful Improvements in IntakeUnloaders for Compressor Service, of which the following is a specification;

The general object of my present invention is the provision of means for equalizing the pressure on the driving piston and the, chamber leading to the intake valve or valves of the compressor cylinder when the intake unloader is on the point of opening to, let atmospheric pressure into the intake chamber of the compressor cylinder.

To the attainment of the foregoing the invention consists in the peculiar and advantageous intake unloader, hereinafter described and definitely claimed.

In the accompanying drawings, made a part hereof:

Figure 1 is a sectional view of the intake unloader constituting the best practical embodiment of my invention of which I am cognizant. 1

Fig. 2 is a detail perspective of the piston complementary to the automatic means for controlling the relation of pressure between the chambers K and L of the unloader.

Similar letters of reference designate corresponding parts in both views of the drawmgs.

By particular reference to Fig. 1, it will be observed that the unloader casing contains chambers S and K, the chamber S being designed to be connected at A with the atmosphere or with any other source of supply to the compressor, and the chamber K being adapted to be attached at B to the intake of a compressor cylinder. Intermediate the chambers S and K is a partition A in which is a port A surrounded by a valve seat A. The arrows in Fig. 1 indicate the direction of travel of the air. The intake unloader consists of a driving piston C, a piston rod E, a plate or body D, a spring F and a rod F bearing an abutment F for the spring F and disposed in a bearing G which also afi'ords an opposite abutment for the spring and a valve casing N. At H is a standard regulator for operating and controlling the piston C by cooperation with the automatic means J for controlling the relation of pressure between the cham ber K and the chamber L at the opposite hereby Specification of Letters Patent.

PatentedDec. 9, 1919. Serial No.'297,828.

side of the chamber S. The regulator H includes a piston O, a regulating spring P, and. a screw Q for adjusting ing of the automatic means J. In the said casing of the means J is a piston T together with an additional piston: portion T anda spring Z. Y r

In applying my improvement, the-pipe M is connected to the air recelver to which the compressor may be attached, and in'the operation of the unloader, the piston O of the regulator H rises againstthe tension of the piston C with reference to the the tenslon of said spring. A pipe M leadsto the chamber of the 'regu-L lator H at the inner side of the piston' 0,.

is a minute the chamber s rin P coincident with the raisin of the P a g pressure to the predetermined point. This permits air or other fluid under pressure to pass through the duct B into thechamber L, whereupon the pressure first forces the piston T against itsseat U, with the result that connection between the chambers L and K is cut off or interrupted. Secondly, the pressure alluded to forces the piston C clownwardly until the valve plate body D bears upon its seat A From this it follows that the connection between the source of supply and the intake of the compressor cylinder is cut off. Following a predetermined drop of pressure, the compressed air in the chamber L escapes through the vent W, and then when the pressure is almost reduced to atmospheric pressure in the chamber L, the piston T is moved away from its seat U by the eX- pansion of the spring Z. This is brought about by the employment of the piston T" fixed with respect to the piston T. In consequence communication is reestablished between the chambers K and L; also, the spring F is only called upon to overcome the friction of the piston C and the weight thereof, in order to force the valve plate body D away from the seat A The stem of the pistons T T fits loosely in the casing to afford atmospheric pressure above the piston T.

It will be apparent from the foregoing that I have provided an intake unloader in which a very light spring may be used, and one in which when closed the valve plate body D is held lightly against its seat, and

in which when on the point of opening there is no vacuum calculated to hold the valve plate body 1) to the seat A This latter is due to the fact that the automatic means J equalizes the oressure in the chambers K and L and neutra izes the atmospheric pressure imposed on the valve plate body'D. From this it follows that not only is it feasible to employ a very light spring F, but at the same time the shock and strain imposed upon the compressor with an intake unloader of the ordinary type, is eliminated.

Having described my invention, what I claim and desire to secure by Letters-Patout, is:

1. An intake unloader including a regulator and means for equalizing the pressure in the intake chamber of a compressor cylinder and on the driving piston of the unloader when the regulator of the unloader interrupts the supply of fluid under pressure to said driving piston.

2. An intake unloader including a regulator and comprising means for equalizing the pressure at the outlet side of the unloader casing and on the driving piston of the unloader when the regulator of the unloader cuts off communication of compressed air to said driving piston.

3. In an intake unloader including a regulator, the combination of a driving piston, means for equalizing the pressure at the outlet side of the unloader casing and on said driving piston when the regulator of the intake unloader cuts off communication of compressed air to said driving piston.

4:. An intake unloader comprising a casing in which are chambers direct communication driving piston, the said driving piston, a regulator in communication with an additional chamber in the casing, and means intermediate said additional chamber and one of the first-named chambers for equalizing the pressure at the outlet side of the unloader casing and on the driving piston when the regulator cuts ofi communication of compressed air to the driving piston.

In testimony whereof I affix my signature.

CHARLES WAINWRIGHT.

between which is controlled by a 

